Signal Output Circuit With Capacitance Compensation Against Flash On/Off
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing signal output circuits using small-size MOSFETs fail to prevent the flash on/off phenomenon due to reduced junction capacitance, which is essential for preventing flash-on and shortening off delay times.
Innovation Solution
A signal output circuit configuration that includes a signal conversion element, a signal output transistor, first and second resistor elements, a diode, a malfunction-prevention transistor, and a capacitance-compensating capacitor, which compensates for reduced junction capacitance by establishing conduction paths and ensuring effective discharge, thereby preventing flash on/off phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the signal output transistor is reduced, then the device size is decreased, but the junction capacitance is reduced causing the flash on/off phenomenon to occur
Solution Approach 1:
The patent introduces a capacitance-compensating capacitor as an intermediary component connected in parallel with the signal output transistor. This external capacitor compensates for the reduced junction capacitance of the miniaturized transistor, maintaining the necessary capacitance value to prevent flash on/off phenomenon while allowing the transistor itself to be small in size.
Solution Approach 2:
The patent changes the parameter configuration by adding an external capacitance element to compensate for the reduced junction capacitance. Instead of relying solely on the intrinsic junction capacitance of the transistor (which decreases with size reduction), the system uses the sum of junction capacitance and external capacitance to maintain the required electrical characteristics.
2Volume of moving object
If the junction capacitance of the transistor is decreased through size reduction, then the device size is reduced, but the ability to prevent unwanted current flow is compromised
Solution Approach 1:
The capacitance-compensating capacitor serves as an intermediary that provides the necessary capacitive effect to prevent unwanted current flow during switching transitions. This external component compensates for the insufficient junction capacitance of the small-size transistor, thereby preventing harmful current flow paths.
Solution Approach 2:
The patent applies beforehand cushioning by pre-charging the capacitance-compensating capacitor during the off state, so that when the transistor switches on, the capacitor provides the necessary current suppression effect immediately, preventing flash on/off phenomenon before it can occur.
3Device complexity
If a small-size transistor is used, then the device complexity is reduced, but the delay time control becomes insufficient due to reduced junction capacitance
Solution Approach 1:
The patent adjusts the time-related parameter by adding external capacitance to control the charging and discharging time constants. The capacitance-compensating capacitor, together with the series resistor, creates a time constant that controls the delay time, compensating for the reduced junction capacitance effect in small-size transistors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed configuration effectively prevents flash on/off phenomena and maintains suitable delay times even with small-size signal output transistors, ensuring reliable operation and noise resistance by compensating for reduced capacitance, thus allowing for size reduction without compromising performance.
Implementation Method 1
converts an input electrical signal to an optical signal, converts the optical signal to an electrical signal
Implementation Method 2
converts the optical signal to an electrical signal
Implementation Method 3
capacitance-compensating capacitor, which compensates for reduced junction capacitance
Implementation Method 4
The diode is connected in parallel to the second resistor element in a direction in which current flows between the signal output terminal of the signal conversion element and the first conduction control terminal
Data Source
AI summary
A signal output circuit includes a signal conversion element, a signal output transistor, a first resistor element, a second resistor element, a diode, a malfunction-prevention transistor, and a capacitance-compensating capacitor. The signal output transistor establishes electrical conduction between two conductive terminals when an on signal is supplied to a conduction control terminal via the signal conversion element. The diode is connected in parallel to the second resistor element in a direction in which current flows between a signal output terminal of the signal conversion element and the conduction control terminal of the signal output transistor when an on signal is outputted to the signal output terminal. The malfunction-prevention transistor establishes electrical conduction between two conductive terminals when a current flows through the second resistor element in a direction opposite the direction of the diode. The capacitance-compensating capacitor is connected in parallel to the second resistor element.